Materials Science Forum Vol. 1136

Abstract: This paper discusses the fire and heat resistance of a polylactic acid/Hemp/Polypropylene hybrid laminated composite. Hybrid composites had their impacts analysed, specifically with regards to the fibre composition and stacking order. Using a hot press, the hybrid composites were created. In this work, Hemp/Polypropylene-reinforced polylactic hybrid composites with thermogravimetric, differential calorimetric, dynamic mechanical, and flamability properties were reported. Thermomechanical studies show that hybridization affects the laminate’s viscoelastic characteristics and thermal stability. Hybrid composites' burning rates were also evaluated for this flammability test. Most of the Hemp layers in sample C7 had the most char residue (10%), while sample C8 had the highest decomposition temperature (450°C). When it comes to hybrid composites, however, the C5 sample offers the best results, with a large char production and a low burning rate of just 36 mm/min. Also, viscoelastic properties like storage and loss modulus are best in class for the C5 sample, which is a hybrid composite. Keywords: Hemp; flammability Polypropylene; PLA; TGA; DSC.

Abstract: Mechanical and thermal properties of composites reinforced with Banana fibre (BF) and Sisal fibre (SF) were investigated in this study. Benzoylation therapy was effective for Banana fibre /Sisal. The hybridised bio-composites (PP/BF/SF) with a total 10 weight percentage were produced using three different fibres ratios between Banana fibre - and Sisal-treated. The thermal stability experiments are performed using thermogravimetric analysis (TGA) and diffraction scanning calorimetry (DSC). According to flammability test results, the treated hybrid composite (BF / PP /SF) burned at the slowest rate (only 28 mm/min) and the stiffness damping factor (Tan δ). The loss modulus (E "the ideal (PP/BF/SF) hybrid composite, T-BF5SF5, has a damping factor of 0.058 and a modulus of 86.2 (MPa). Thermomechanical analysis (TMA) was also used to effectively record the dimensional coefficient (m) versus temperature studies, with T-BF5SF5 achieving the highest dimensional coefficient (m) of 30.11 at 110°C. Keywords: Sisal; biocomposites; Banana fibre ; dynamic mechanical analysis; thermal; benzoylation.

Abstract: The sepiolite and Al₂O₃-doped sepiolite contents in the as-received sepiolite/epoxy systems were maintained at 2 and 4wt %, respectively. The flame-retardant capabilities and combustion behavior of Al₂O₃-doped sepiolite in epoxy resin were meticulously evaluated through a series of tests including cone calorimetry (CC), limiting oxygen index (LOI), dynamic mechanical analysis (DMA), and thermogravimetric analysis (TGA). Several features, including degradation kinetics, combustion characteristics, thermomechanical properties, flame retardancy, and thermal degradation were evaluated with the intention of drawing comparisons to standard sepiolite. The findings from the studies were positive. In contrast, Al₂O₃-doped sepiolite not only further improved the LOI values and char formation post-cone testing but also decreased the previously mentioned combustion-related parameters in the composites. A potential synergistic interaction between sepiolite and Al₂O₃ in augmenting the flame retardancy of the composite was suggested. The thermal degradation of composites was only little affected by addition of sepiolite, although Al₂O₃-doped sepiolite addition seemed to speed up the deterioration process. The epoxy composite’s glass transition temperature (Tg) was shown to increase when sepiolite or Al₂O₃-doped sepiolite was added, as determined by DMA. The findings presented in this research provided a practical approach to improving the fireproofing of polymers. Keywords: Al2O3-doped sepiolite; TGA, flame retardancy; DSC, epoxy; thermal properties.

Abstract: This study investigates two-dimensional composites with Cu/Ni laminated and brick-mortar structures using the GTN constitutive model and mathematical plane tessellation schemes. Uniaxial and biaxial stretching behaviors are analyzed by precisely controlling the model microgeometries through finite element numerical simulations. The results indicate that the laminated structure, represented by triangular tessellation models, exhibits stretching-dominated deformation when uniaxial stretching is applied along the direction of the hard phase laminae, demonstrating exceptional strength. In contrast, the brick-mortar structure, also represented by triangular tessellation models, undergoes deformation through a combination of bending and stretching (compression), enhancing plasticity while maintaining significant strength. By examining the relationship between microstructure and mechanical properties in these two-phase composites, this study provides valuable insights for material synthesis through structural patterning.

Abstract: Ultrafiltration membranes have been widely used in industrial technology due to their high removal effectiveness. Long-term use of membranes will reduce membrane performance, so cleaning is required to maintain stable membrane performance. Chemical cleaning has proven to be effective for removing impurities but can also have a negative impact on membrane life. Polyethersulfone (PES) is proven to have strong mechanical properties due to its hydrophobic nature, but this hydrophobic nature makes PES membrane performance less than optimal so a hydrophilic pluronic co-polymer is needed. The combination of these two materials produces a membrane with optimal performance and a relatively long usage time. In addition, this research also aims to compare pure PES (P) and PES/Pluronic (PP) membranes against cleaning using sodium hypochlorite (NaOCl). The results show that the membrane with the addition of pluronic has more stable characteristics than the pure PES membrane. The morphological structure shows a very significant difference after the addition of pluronic, the PES membrane has a finger-like pore structure that is sparse compared to the PES/Pluronic membrane. Based on the data obtained, the water contact angle (WCA) of the washed membrane with NaOCl was higher than the original membrane. The WCA of pure PES membrane increased from 59.5o to 67.5o after cleaning. On the other hand, the WCA of PES/Pluronic membrane was increased from 56.8o to 63.7o after cleaning.

Abstract: Modification of polymer solution with various additive is generally conducted to improve the membrane performance. In this study, we investigate the modification of Polyvinylidene fluoride (PVDF) membranes by addition of cellulose nanocrystals (CNC) into polymer solution. The effect of the addition of 0.5 wt% of CNC was studied in detail on the membrane structure, water content, and its filtration performance. The water content of the modified PVDF membrane with CMCs was higher than that of the pristine PVDF membrane. Pure water flux shows a similar trend with the addition of 0.5wt% CNC, which correlates with the results of porosity and membrane swelling tests. The increase in water content, permeability, porosity, and swelling indicates an improvement in the antifouling properties of the membrane. This research provides insight that the addition of CNC enhances the performance of PVDF polymer membranes for use in water treatment.

Abstract: The process of synthesizing polyurethane (PU) membranes typically involves linking together networks of polymers using organic materials like polyols and isocyanates. Subsequent investigations used additional inorganic substances within PU polymers to enhance the mechanical and thermal characteristics of membranes. In order to be used as a sensor matrix, the PU membrane needs to have certain good qualities and be able to firmly attach to ions. Hence, further refinement of the membrane is necessary in order to enhance these attributes. The PU membrane made from castor oil (Ricinus communis L.) was changed in this study by adding ĸ-carrageenan and D2EHPA. The composition of the membrane plays a crucial role in governing the creation of hard and soft segments within the membrane structure. The right membrane composition can be found by using Expert Version 13 software for process design. This software is based on the Response Surface Methodology and uses Box-Behnken Design. The primary aim of this study was to fabricate PU membranes utilizing natural resources while ensuring the attainment of desirable qualities. The R² and PRESS values, which are very important for figuring out how important the physical performance response is, led to the choice of the quadratic model design as the best one. One of the experimental conditions was the use of 0.231 mg of D2EHPA, 1.241 mg of κ-carrageenan, and 3.840 g of acetone. The final mixture was predicted to have a visual scale value of 6.5 so that a membrane with the best physical properties in terms of strength and flexibility could be made. The composite-derived PU membrane has favorable physical performance. The findings of this study can serve as a foundational element for the advancement of PU membranes in a wide range of prospective applications.

Abstract: The wrought magnesium alloy AZ80, comprising 8 wt% aluminum, underwent fabrication via permanent steel mold casting (PSMC), involving three distinct stages with wall sizes measuring 6 mm, 10 mm, and 20 mm. The numerical simulation of the solidification showed that the cooling rate of the step casting increased, when the wall size decreased. The as-cast alloy's microstructure underwent scrutiny through optical microscopy and scanning electron microscopy (SEM), complemented by energy dispersive spectroscopy (EDS) analysis. Findings from the microstructure examinations unveiled the presence of primary Mg phase across all three sections of the cast AZ80 alloy, accompanied by micron and nanosized Mg-Al-Zn intermetallic phases, as well as micron-sized Al-Mn intermetallic phases. But the intermetallic contents increased, and the dendrite sizes and the porosity levels decreased, as the wall sizes reduced. The tensile testing results revealed significant findings regarding the ultimate tensile strength (UTS), yield strength (YS), modulus, resilience, and toughness, increased, when the wall sizes decreased to 6 from 20 mm. The negative effect of large casting wall sizes on ductility was demonstrated. Exceptional tensile properties of the thin wall resulted from fine dendritic structure, high intermetallic content, and minimal porosity level.

Abstract: The effects of different rolling and normalization processes on the microstructure, grain size, and mechanical properties of steel plates were investigated using the design philosophy of low C and low Mn composition. The results demonstrate the high strength and toughness of the steel plate through the efficient use of properly controlled rolling. The steel plate obtained by normalizing at 920 °C has a uniform and fine internal microstructure and all mechanical properties fully meet the standard requirements. The steel plates obtained by this process, with moderate strength and toughness, meet the standard requirements and are capable of stable batch production.